Cloud Computing Interview Questions

> What is a cloud?

A cloud is a combination of hardware, networks, storage, services, and interfaces that helps in delivering computing as a service. It has broadly three users which are end user, business management user, and cloud service provider. The end user is the one who uses the services provided by the cloud. The business management user in the cloud takes the responsibility of the data and the services provided by the cloud. The cloud service provider is the one who takes care or is responsible for the maintenance of the IT assets of the cloud. The cloud acts as a common center for its users to fulfill their computing needs.

> Explain cloud computing?

Cloud computing is the method of accessing several servers world wide by the devices such as net book, laptop, personal computers smart phones and other devices with digital network such as WAN (wide area connection ) or any internet connection for using world wide web.

> Explain the benefits of cloud computing?

There are numerous benefits of cloud computing including data backup and storage of data, powerful server capabilities, software asa service known as (SaaS), Information technology sandboxing capabilities etc.

> Name few platforms which are used for large scale cloud computing?

There are many platforms available for cloud computing but to model the large scale distributed computing the platforms are as follows:

1. MapReduce: is software that is being built by Google to support distributed computing. It is a framework that works on large set of data. It utilizes the cloud resources and distributes the data to several other computers known as clusters. It has the capability to deal with both structured and non-structured data.

2. Apache Hadoop: is an open source distributed computing platform. It is being written in Java. It creates a pool of computer each with hadoop file system. It then clusters the data elements and applies the hash algorithms that are similar. Then it creates copy of the files that already exist.

> Explain different layers which define cloud architecture?

Cloud computing architecture consists of many layers which help it to be more organized and can be managed from one place. The layers are as follows:

1. Cloud controller or CLC is the top most level in the hirerachy which is used to manage the virtualized resources like servers, network and storage with the user APIs.

2. Walrus is used for the storage and act as a storage controller to manage the demands of the users. It maintains a scalable approach to control the virtual machine images and user data.

3. Cluster Controller or CC is used to control all the virtual machines for executions the virtual machines are stored on the nodes and manages the virtual networking between Virtual machines and external users.

4. Storage Controller or SC provides a storage area in block form that are dynamically attached by Virtual machines.

5. Node Controller or NC is at the lowest level and provides the functionality of a hypervisor that controls the VMs activities, which includes execution, management and termination of many instances.

> What essential things a user should know before going for cloud computing platform?

A user should know some parameters by which he can go for the cloud computing services. The parameters are as follows:

1. User should know the data integrity in cloud computing. It is a measure to ensure integrity like the data is accurate, complete and reasonable.

2. Compliance: user should make sure that proper rules and regulations are followed while implementing the structure.

3. Loss of data: user should know about the provisions that are provided in case of loss of data so that backup and recovery can be possible.

4. Business continuity plans: user should think about does the cloud services provide him uninterrupted data resources.

5. Uptime: user should know about the uptime the cloud computing platform provides and how helpful it is for the business.

6. Data storage costs: user should find out about the cost which you have to pay before you go for cloud computing.

> What are some open source cloud computing platform databases?

Cloud computing platform has various databases that are in support. The open source databases that are developed to support it is as follows:

1. MongoDB: is an open source database system which is schema free and document oriented database. It is written in C++ and provides tables and high storage space.

2. CouchDB: is an open source database system based on Apache server and used to store the data efficiently

3. LucidDB: is the database made in Java/C++ for data warehousing. It provides features and functionalities to maintain data warehouse.

> What are some examples of large cloud providers and their databases?

Cloud computing has many providers and it is supported on the large scale. The providers with their databases are as follows:

• Google bigtable: it is a hybrid cloud that consists of a big table that is spilt into tables and rows. MapReduce is used for modifying and generating the data.

• Amazon SimpleDB: is a webservice that is used for indexing and querying the data. It allows the storing, processing and creating query on the data set within the cloud platform. It has a system that automatically indexes the data.

• Cloud based SQL: is introduced by Microsoft and it is based on SQL database. it provides data storage by the usage of relational model in the cloud. The data can be accessed from the cloud using the client application.

> What are the security laws which take care of the data in the cloud?

The security laws which are implements to secure data in the cloud are as follows:

Input validation: controls the input data which is being to any system.

Processing: control that the data is being processed correctly and completely in an application.

File: control the data being manipulated in any type of file.

Output reconciliation: control the data that has to be reconciled from input to output.

Backup and recovery: control the security breaches logs and the problems which has occurred while creating the back.

> What are different data types used in cloud computing?

Cloud computing is going all together for a different look as it now includes different data types like emails, contracts, images, blogs, etc. The amount of data increasing day by day and cloud computing is requiring new and efficient data types to store them. For example if you want to save video then you need a data type to save that. Latency requirements are increasing as the demand is increasing. Companies are going for lower latency for many applications.

> How the cloud services are measured?

Cloud computing provides the services to the organizations so they can run their applications and install them on the cloud. Virtualization is used to deploy the cloud computing models as it provides a hidden layer between the user and the physical layer of the system. The cloud services are measured in terms of use. Pay as much as you use that can be on the basis of hours or months or years. Cloud services allow users to pay for only what they use and according to the demand the charges or the prices gets increased.

> What is the difference between traditional datacenters and cloud?

Cloud computing uses the concept of datacenter as it is the datacenter is based on the tradition one so the difference between them are as follows:

• Cost of the traditional datacenter is higher, due to heating issues and other hardware/software related issues but this is not the case with the cloud computing infrastructure.

• It gets scaled when the demand increases. Most of the cost is being spent on the maintenance being performed on the datacenters, whereas cloud platform requires minimum maintenance and not very expert hand to handle them.

> What is the security aspects provided with cloud?

Security is one of the major aspects which come with any application and service used by the user. Companies or organizations remain much more concerned with the security provided with the cloud. There are many levels of security which has to be provided within cloud environment such as:

• Identity management: it authorizes the application service or hardware component to be used by authorized users.

• Access control: permissions has to be provided to the users so that they can control the access of other users who are entering the in the cloud environment.

• Authorization and authentication: provision should be made to allow the authorized and authenticated people only to access and change the applications and data.

> What are the different modes of software as a service?

Software as a Service provides cloud application platform on which user can create application with the tools provided. The modes of software as a service are defined as:

1. Simple multi-tenancy: in this each user has its own resources that are different from other users. It is an inefficient mode where the user has to put more time and money to add more infrastructure if the demand rises in less time to deliver.

2. Fine grain multi-tenancy: in this the functionality remains the same that the resources can be shared to many. But it is more efficient as the resources are shared not the data and permission within an application.

> What is the use of API's in cloud services?

API stands for Application programming interface is very useful in cloud platforms as it allows easy implementation of it on the system. It removes the need to write full fledged programs. It provides the instructions to make the communication between one or more applications. It also allows easy to create application with ease and link the cloud services with other systems.

> What are the different datacenters deployed for this?

Cloud computing is made up of various datacenters put together in a grid form. It consists of different datacenters like:

• Containerized Datacenters:

These are the traditional datacenters that allow high level of customization with servers, mainframe and other resources. It requires planning, cooling, networking and power to access and work.

• Low-Density Datacenters:

These datacenters are optimized to give high performance. In these datacenters the space constraint is being removed and there is an increased density. It has a drawback that with high density the heat issue also creeps in. These datacenters are very much suitable to develop the cloud infrastructure.

> What are the different deployment models?

Cloud computing supports many deployment models and they are as follows:

• Private Cloud:

Organizations choose to build there private cloud as to keep the strategic, operation and other reasons to themselves and they feel more secure to do it. It is a complete platform which is fully functional and can be owned, operated and restricted to only an organization or an industry. More organizations have moved to private clouds due to security concerns. Virtual private cloud is being used that operate by a hosting company.

• Public Cloud:

These are the platforms which are public means open to the people for use and deployment. For example, google, amazon etc. They focus on a few layers like cloud application, infrastructure providing and providing platform markets.

• Hybrid Clouds:

It is the combination of public and private cloud. It is the most robust approach to implement cloud architecture as it includes the functionalities and features of both the worlds. It allows organizations to create their own cloud and allow them to give the control over to someone else as well.

> What does software as a service provide?

Software as Service is another layer of cloud computing, which provides cloud applications like google is doing, it is providing google docs for the user to save their documents on the cloud and create as well. It provides the applications to be created on fly without adding or installing any extra software component. It provides built in software to create wide varieties of applications and documents and share it with other people online.

> How important is platform as a service?

Platform as a Service is an important layer in cloud architecture. It is built on the infrastructure model, which provides resources like computers, storage and network. This layer includes organizing and operate the resources provided by the below layer. It is also responsible to provide complete virtualization of the infrastructure layer to make it look like a single server and keep it hidden from the outside world.

> What resources are provided by infrastructure as a service?

Infrastructure as a Service provides physical and virtual resources that are used to build a cloud. Infrastructure deals with the complexities of maintaining and deploying of the services provided by this layer. The infrastructure here is the servers, storage and other hardware systems.

> What is the difference between scalability and elasticity?

Scalability is a characteristic of cloud computing through which increasing workload can be handled by increasing in proportion the amount of resource capacity. It allows the architecture to provide on demand resources if the requirement is being raised by the traffic. Whereas, elasticity is being one of the characteristic provide the concept of commissioning and decommissioning of large amount of resource capacity dynamically. It is measured by the speed by which the resources are coming on demand and the usage of the resources.

> How does cloud computing provides on-demand functionality?

Cloud computing is a metaphor used for internet. It provides on-demand access to virtualized IT resources that can be shared by others or subscribed by you. It provides an easy way to provide configurable resources by taking it from a shared pool. The pool consists of networks, servers, storage, applications and services.

> What are the advantages of cloud services?

Some of the advantages of cloud service are given as follows:

• Helps in the utilization of investment in the corporate sector; and therefore, is cost saving.

• Helps in the developing scalable and robust applications. Previously, the scaling took months, but now, scaling takes less time.

• Helps in saving time in terms of deployment and maintenance.

> Which services are provided by Window Azure operating system?

Windows Azure provides three core services which are given as follows:

• Compute

• Storage

• Management

> What can be done using cloud computing?

Cloud applications are very speedy and without buying and installing softwares we can use it. Application building in this is five times faster and it can deploy an application any time and any where and also it makes applications instantly collaborative and mobile.

> Why Cloud is necessary?

Amongst those who are already using the cloud, 94 % said the infrastructure was an important part of their decision but there is not one universal cloud infrastructure which suits every environment.

> Explain hybrid and community cloud?

The hybrid cloud consists of multiple service providers. This model integrates various cloud services for Hybrid Web hosting. It is basically a combination of private and public cloud features. It is used by the company when a company has requirements for both the private and public clouds. Consider an example when an organization wants to implement the SaaS (Software as a Service) application throughout the company.

The implementation requires security that can be provided by the private cloud used inside the firewall. The additional security can be provided by the VPN on requirement. Now, the organization has both the private and public cloud features.

The community cloud provides a number of benefits, such as privacy and security. This model, which is quite expensive, is used when the organizations having common goals and requirements are ready to share the benefits of the cloud service.

> Explain the role of performance cloud in cloud computing?

 It is an immerging type of cloud which can transfer maximum amount of data instantly. Basically it is used by Professional computer garners which play the games online and works on high performance computing research.

> Why professional clouds are required in Cloud computing?

Professional clouds are used in Cloud computing because professional clouds are used for Emails, CRM solutions and web sites etc.

> What are the advantages of cloud services?

Some of the advantages of cloud service are given as follows:

• Helps in the utilization of investment in the corporate sector; and therefore, is cost saving.

• Helps in the developing scalable and robust applications. Previously, the scaling took months, but now, scaling takes less time.

• Helps in saving time in terms of deployment and maintenance.

> Which services are provided by Window Azure operating system?

Windows Azure provides three core services which are given as follows:

• Compute

• Storage

• Management